The present invention relates to volumetric valves which close automatically when a predetermined quantity of liquid has passed through.
The technical field of the invention is the construction of volumetric valves and in particular irrigation valves.
Irrigation or volumetric valves are known which have a programming device on which is displayed a given volume and which close automatically when they have discharged the displayed volume. These valves have a turbine which is rotated by the water passing through the valve, which by means of a reducing gear train drives a resetting and display button and a cam which automatically controls the closing of the valve flap when the button has turned by a predetermined angle. After each operating cycle, it is necessary to reset the volumetric valves so that they are ready for a new cycle. Resetting is brought about by turning the display button by an angle which determines at the same time the displayed volume for the new cycle.
A first disadvantage is that a resetting is obtained by rotating the display button which makes the resetting by hydraulic means more difficult to obtain than by a translation movement.
Another disadvantage is that the resetting and display of a new flow are realized by one and the same button. Therefore, this operation requires a certain amount of attention to be paid, although frequently the volumes to be displayed remain unchanged for successive cycles, the operator having to remember the reference values which are not displayed.
A third disadvantage which directly results from the two abovementioned disadvantages is that remote control of the resetting process is difficult and even impossible to obtain which complicates the operation of the systems, permitting neither cascade operations in which the closing of one volumetric valve automatically remotely controls the resetting of the following valve, nor closed loop operation evolving from the first operation.